1. Field of the Invention
The invention relates to a flame barrier arrangement, having at least two flame barrier elements which are arranged one behind the other in the direction of flow of a combustible gas and have a multiplicity of gaps for extinguishing a flame impinging on the surface of a flame barrier element, and having at least one spacer element between flame barrier elements, in order to produce a space between adjacent flame barrier elements.
2. Background Description
Flame-arresting fittings having a flame barrier, which prevents the spread of flames from explosions, detonations or permanent fires and therefore prevents flames from breaking through, are used to protect against explosions, detonations and permanent fires. A wide range of different designs of flame barriers are known and can be categorized substantially as static dry flame barriers, static wet flame barriers and dynamic flame barriers.
Most flame-arresting fittings which are currently in use are equipped with static dry flame barriers. These are elements in which use is made of the discovery that flames are no longer able to react within tight gaps, maintaining suitable limit dimensions, and therefore are made to go out. In this case, a flame is generally extinguished by intimate contact between the flame and cooling walls, e.g. by guiding the flame through narrow gaps.
Flame barriers of this type can be designed as narrow-mesh screens, plate safety features, sintered metals, beds of beads and strip safety features. The essential factor is that the flame barrier gaps which are selected for safety can be reproducibly maintained within very tight tolerances. Therefore, nowadays, it is primarily strip safety features which are used, these features being produced by winding up in each case one smooth strip and one corrugated strip. The corrugated strip is provided with corrugations which are straight or directed to the left or right and define the gap width, which is in the range from 0.2 to at most 1.5 mm, depending on the explosive mixture.
Depending on the type of flame-arresting fitting (explosion, detonation or permanent fire safety features), two, three or more strip securing discs are combined as flame barrier elements, optionally together with a surrounding cage in order to increase the mechanical strength, to form a complete flame barrier.
A flame barrier of the generic type is disclosed, for example, in EP 0 375 455 A2, which shows a flame-arresting fitting with a flame barrier comprising four flame barrier elements which are arranged one behind the other in the direction of flow of a combustible gas. Narrow spaces which create an expansion zone for the gas in the gaps and lead to turbulent flow of the gas are provided between the individual flame barrier elements. The spaces are produced by spacer elements between the flame barrier elements.
The conventional spacer elements are usually laid loosely between the flame barrier elements during assembly of a multilayer flame barrier. The spacer elements are in this case formed, for example, from a continuous triangular, polygonal or loop-like wire ring.
Particularly in the case of flame barriers with relatively large diameters, the conventional spacers offer only insufficient mechanical strength. The relatively expensive flame barrier elements can easily be destroyed in the event of dismantling or cleaning. Under high loads, in particular in the event of unstable detonations, the flame barrier elements are deformed when using the conventional spacers, so that the space between adjacent flame filter elements is reduced.